The present invention relates to the apparatus for bending metal plates by the use of special metal molds. Particularly, this apparatus is characterized in that it is provided with the rotary control function, cushion materials, etc. Such apparatus is used as a bender for bending metal plates (press brake), oil pressure press, air pressure press, mechanical press, etc.
In addition, the present invention relates to the apparatus for bending metal plates in U-shape by the use of two (2) lower bar molds semicircular in section. This apparatus is characterized in that the tip-rounded upper mold is used, the lower bar molds are provided with rotary control function and that the odd part/parts of lower bar molds are cut off to form an odd pressing part/parts. Such apparatus is used as a bender for bending metal plates (press brake), oil pressure press, air pressure press, mechanical press, etc. in a U shape, such metal plates bent being used for buildings, kitchens, rail-guides, cooling fans, oval pipes, etc.
Regarding the apparatus for bending metal plates by the use of metal molds, such as, for an example, xe2x80x9ca benderxe2x80x9d, there have been conventionally used the lower plane molds provided with a groove thereon and the upper punching mold. The metal plate is placed on the groove on the lower plane molds. Then, the metal plate is pressed into the groove of the lower mold and thereby bent.
However, there are disadvantages in the above apparatus. Since the groove between the lower plane molds is limited in size and shape, several scores of the lower plane molds provided with the different size and shape of grooves are required to be prepared for taking care of the different thickness of the metal plate to be bent and the different bending degree required. This causes a larger cost in equipment. Not only that, but a space is required for storing such number of the lower plane molds. This is a problem in terms of space economy. Furthermore, the lower mold is required to be changed, whenever necessary, depending upon the purpose for which it is used. Thus, the above apparatus is labor-consuming and lowers an operational efficiency.
Particularly, when the thin metal plate is bent, the acute bending accuracy desired is not likely to be obtained because the tip part of the groove is too wide. When the thick metal plate is bent, scratches are liable to be formed on the surface of the metal plate, because the groove gets tight in its tip part.
In addition, the pressure of the upper mold is rectangularly, by way of the metal plate, imposed on the groove between the lower plane molds. As there is no pressure relief, an excessive pressure causes the friction between the surface of the metal plate and the groove surface of the lower mold. Thus, there are formed scratches on the surface of the metal plate. Such scratches produce the inferior appearance on the products made of the metal plate bent in such manner. This is another disadvantage.
Furthermore, as the pressure of the upper mold is linearly concentrated on the surface of the metal plate with the groove between the lower molds at the supporting point, the physical texture of the metal plate is damaged and deteriorated. Thus, cracks are produced therein. The physical strength thereof is lowered. When, particularly, the shoulder R of the metal plate is small, this defect is conspicuously developed.
Furthermore, the stroke of the upper mold reaches the lower dead point and bends the metal plate. Because of this mechanism, the strong pressure of the upper mold is directly transferred to the groove between the lower molds. Thus, the impact thereof is large. Scratches and damages are caused on the groove surface between the lower plane molds. The groove between the lower mold tends to be abraded and worn out. These are the disadvantages of the conventional molds.
Furthermore, the metal plate is placed on the groove between the lower plane molds and then bent by pressing it down by the upper mold. When the tip part of the metal plate is bent or when the bending length is too short, the metal plate tends to get out of place. Even when the tip part of the metal plate can be bent, the bending accuracy thereof tends to be insufficient or unsatisfactory.
Then, we have made a considerable study of the conventional apparatus for bending metal plates. As a result, there has been developed the apparatus for bending metal plates involving the use of entirely new special lower molds. The patent application has been filed for it (Application No. Hei-10-373221). Thus, there have been overcome the aforementioned problems and disadvantages of the conventional apparatus for bending metal plates.
Referring to the metal bending apparatus involving the use of the special lower molds, the metal mold comprises the ordinary upper punch mold 1 and two (2) lower bar molds 2a and 2b semicircular in section having metal contact surfaces 3a and 3b on their surfaces, as shown in FIG. 1. Further, the reverse surfaces 5a and 5b of these two (2) lower bar molds are placed so as to rotate slidably, as shown in FIG. 2, on the two (2) concave surfaces, having the groove 7 in between, formed on the support 4.
Then, referring to the metal plate 8 bending mechanism, the metal plate 8 is placed on the metal contact surfaces 3a and 3b of two (2) lower bar molds 2a and 2b. As shown in FIG. 3, the metal plate 8 is downwardly pressed by the upper mold 1. Simultaneously, the metal contact surfaces 3a and 3b of two (2) lower bar molds 2a and 2b are caused to rotate inwardly and the metal plate 8 is bent in V-shape.
As mentioned above, the metal plate bending apparatus involving the use of the special lower mold is unlike the conventional plane lower molds. Thus, it is not required to use scores of plane lower molds different in size and shape, depending upon the thickness of metal plates to be bent. It is provided with such function as to bend metal plates to an optional degree by the use of lower molds comprising one or a few sets of lower bar molds 2a and 2b. Because of this function, facility cost is lowered and a storing place is made smaller. There is no need to change lower molds. Thus, operational efficiency, etc. is improved. These are advantages thereof.
Further, when bending the metal plate 8, the downward pressure of the upper mold 1 is reduced. Thereby, the downward pressure of the upper mold 1 is caused to run off by way of the metal plate 8. Thus, there would be produced no scratches on metal plates 8 to be caused by the friction of the metal plate 8 against the lower bar molds 2a and 2b. Thus, the metal 8 has a good outer appearance.
However, when bending the thick metal plate 8 by the downward pressure of the upper mold 1, the metal contact surfaces 3a and 3b tends to run off the metal plate 8, probably because the lower bar molds 2a and 2b are rotated too smoothly. As shown in FIG. 4, while the bending angle of the metal plate 8 remains insufficient, the metal plate 8 separates from the metal contact surfaces 3a and 3b. The bent part of the metal plate 8 gets into the groove. The bending angle (R) of the metal plate 8 comes to be insufficient and the desired angle is not satisfactorily obtained. Thus, it is not bent neatly and the bending accuracy is lowered. These are disadvantages of the conventional apparatus.
Furthermore, when attempting to bend the metal plate 8 at an acute angle of less than 90xc2x0 by the aforementioned metal plate bending apparatus, the adjacent parts on the metal contact surfaces of two (2) lower bar molds tend to get apart from each other, as shown in FIG. 4. Thus, the bending angle of metal plate gets loose. Therefore, it was difficult to bend the metal plate 8 at an acute angle of less than 90xc2x0.
In addition, when attempting to bend the metal plate 8 by the aforementioned metal plate bending apparatus, the metal plate 8 is pressed on the metal contact surfaces 3a and 3b of the lower bar mold 2a and 2b thereunder by the upper mold 1. Because of such pressure, scratches, slit scars, etc. are caused by the friction on the lower surface of the metal plate 8, namely, the surface which comes into contact with the metal contact surfaces 3a and 3b of the lower bar molds 2a and 2b. This causes the quality of products lowered. In worst case, products become incapable of being placed on the market.
Further, after the stroke of the upper mold 1 reaches the lower dead point and bends the metal plate 8, the upper mold 1 is caused to return to the original position. Then, the bent metal plate 8 is taken out from the bottom. It is required that the lower bar molds 2a and 2b be caused to rotate inversely so that the metal contact surfaces 3a and 3b may return to the horizontal position. But, in many cases, the lower bar molds 2a and 2b are not capable of being satisfactorily restored to their original positions by their own weight alone. Their restoration requires manual labor. Thus, work inefficiency is lowered. This is another disadvantage.
Further, as mentioned above, there has been the metal bending apparatus involving the use of the upper mold and plane lower molds, such as a bender. This apparatus has been capable of bending a metal plate in V-shape by placing the metal plate on the metal contact surface of plane lower mold and pressing the same metal plate against the plane lower mold. However, for bending the metal plate in U-shape, this apparatus is absolutely required to use several kinds of upper molds and plane lower molds and go through several manufacturing processes. In other words, there has been no apparatus for bending the metal plate in U-shape by the use of the single set of the upper mold and lower mold as well as the single process.
Unlike the conventional metal bending apparatus, the lower plane mold of the present invention is not required to use scores of plane molds in different size and shape. The rotation of two (2) lower bar molds is controlled by the use of one or a few pairs of rotary lower bar molds having such rotary control function as a spring, etc. and then the surface of the metal plate is tightly attached to the metal contact surfaces of two (2) lower bar molds. The downward pressure of the upper mold is properly given to the metal plate. Thus, the metal plate is bent neatly and accurately, adjusting the bending angle (R) thereof in accordance with the object for which it is to be used. Thus, the bending performance thereof is improved. Herein lies the main object of the present invention.
Further, when bending the metal plate by the use of two (2) lower bar molds, the acute bending angle is formed in V-shape on the metal contact surfaces of the lower bar molds. Thereby, the metal plate may be bent at an acute angle of less than 90xc2x0. This is another object of the present invention.
The further object of the present invention is that, when bending the metal plate by pressing the metal plate on the metal contact surfaces of the lower bar molds, there is formed a cushion material surface, sliding surface or sintered carbide surface on the metal contact surfaces of the lower bar mold. Thereby, the formation of scratches, slit scars, etc. is prevented on the lower surface of the metal plate. Thus, the products made of such metal plate bent has a good outer appearance.
Furthermore, there are caused a plurality of units to coexist lengthwise in one row, such units being loaded on the support provided with two (2) concave surfaces. Thereby, it becomes possible to bend the lengthy metal plate which could not be bent by the conventional metal bending apparatus. Herein lies one of the objects of the present invention
Further, the metal contact surfaces of two (2) lower bar molds are not required to be manually restored to the horizontal position. The metal contact surfaces of two (2) lower bar molds are automatically caused to turn inversely and return to the horizontal position. Herein lies likewise one of the objects of the present invention.
Unlike the conventional lower plane mold, the lower plane mold of the present invention is not required to use scores of plane molds different in shape and size for meeting with the required thickness or bending angle of the metal plate to be bent. The metal plate may be optionally bent by the use of one or a few pairs of lower bar molds. Thereby, the equipment cost is reduced and the storing place is made unnecessary or minimized. Further, the present invention makes it unnecessary to change lower molds and thereby improves work performance. This is also one of the objects of the present invention.
The further object of the present invention is that, by receiving the pressure of the upper mold at the entire metal contact surfaces of two (2) lower bar molds, such pressure is dispersed and thereby the physical texture of the metal plate is made free from any damage or deterioration. Thereby, cracks are prevented from being formed on the metal plate. Thus, the physical strength of the metal plate is maintained and the stronger metal plate product is made.
The further main object of the present invention is that the rotation of the two (2) lower bar molds are controlled by the use of one or a few pairs of rotary lower bar molds provided with such rotary control function as a press spring, etc., and the metal plate surface is caused to tightly attach to the metal contact surfaces of two (2) lower bar molds. Thus, the pressure of the tip-rounded upper mold is properly given to the metal plate. Thus, the bending angle (R) of the metal plate is adjusted in accordance with the object for which it is to be used. Thus, the bending performance thereof is improved.
When the metal plate is bent in U-shape by pressing the metal plate on the metal contact surfaces of the lower bar molds and by using the tip-rounded upper mold, there is formed a cushion material surface, sliding surface or sintered carbide surface on the metal contact surface of lower bar mold. Thereby, scratches, slit scars, etc. are prevented from being formed on the lower surface of the metal plate. This contributes to improvement in the outer appearance of the metal plate bent in U-shape. This further contributes to improvement in the quality of bent metal plate products. Herein lies the further object of the present invention.
The present invention relates to the apparatus provided with rotary control function for bending metal plates. There are prepared two (2) lower bar molds semicircular in section. The reverse convex surfaces of two (2) lower bar molds are placed in such manner as to slidably rotate on the support provided with two (2) concave surfaces having the groove in the intermediate thereof. The upper end of the pull-up rod is rotatively attached to the rims or reverse convex surfaces of two (2) lower bar molds. Each pull-up rod is projectively placed on the side of the support, running through the stopper, provided on the support. The push spring is set on the projection of each pull-up rod. Simultaneously, a fixture is attached to the lower end of each pull-up rod. The push spring set on each pull-up rod is retained by the stopper and the fixture. In such state, it is attached to the side of the support. The metal plate is placed on the metal contact surfaces of two (2) lower bar molds. The metal plate is pressed on the lower bar molds by the upper mold. The metal contact surfaces of two (2) lower bar molds are caused to rotate in V-shape for bending the metal plate. In connection therewith, the pull-up rod attached to the support is raised against the resilience of the push spring. Further, the rotation of metal contact surfaces of two (2) lower bar molds are controlled by the rotary control force of the push spring. Thus, the metal plate is neatly and nicely bent. Herein lies the feature of the present invention.
In addition, the adjust screw is slidably attached in such manner as to move vertically, in stead of the fixture to the lower end of each pull-up rod of the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates. The position of the adjust screw is moved, depending upon the bending condition of metal plates. Thus, according as the bending condition of metal plates, the metal plate is neatly and nicely bent. This is one of the feature of the present invention.
Furthermore, cushion material surface is put, or sliding surface or sintered carbide surface is formed on the metal contact surfaces of two (2) lower bar molds of the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates. Thus, the formation of scratches, scars, etc. is prevented on the lower surface of the metal plate. Thus, the product quality thereof is improved. This is one of the features of the present invention.
Furthermore, an acute angle of V-shape is formed in section on the adjacent parts between metal contact surfaces of two (2) lower bar molds of the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates. Thus, the bending angle of the metal plate may be made at an acute angle of less than 90xc2x0. This is one of the features of the present invention.
Furthermore, there is made as one unit the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates. A plurality of these units are caused to coexist lengthwise in one row for bending the lengthy metal plate. This is one of the features of the present invention.
Furthermore, the present invention relates to the apparatus provided with rotary control function for bending metal plates in U-shape. There are lengthwise cut off the odd adjacent parts in L-shape between the metal contact surfaces of two (2) lower bar molds semicircular in section and the odd press parts are formed. The reverse concave surfaces of two (2) lower bar molds semicircular in section are loaded in such manner as to rotate slidably on the support provided with two (2) concave surfaces having the groove in the intermediate thereof. The upper end of pull-up rod is rotatively attached to rims or convex surfaces of two (2) lower bar molds. Each pull-up rod is projectively placed on the side of the support, running through the stopper provided on the support. The push spring is set on the projection of each rod. Simultaneously, the fixture is attached to the lower end of each pull-up rod. The push spring set on each pull-up rod is retained by the stopper and the fixture and, in such state, is attached to the side of the support. The metal plate is placed on the metal contact surfaces of two (2) lower bar molds. The metal plate is pressed on the lower bar molds by the tip-rounded upper mold. After the first stage bend of the metal plate in U-shape, the odd press parts of two (2) lower bar molds are caused to rotate and, for the second stage bend of the metal plate, the pull-up rod attached to the support is lifted up against the resilience of the push spring. The rotation of the odd press parts of two (2) lower bar molds is controlled by the rotary control force of the push spring. Thus, the metal plate is neatly bent in U-shape. This is another feature of the present invention.
In addition, the adjust screw is slidably attached in such manner as to move vertically, in stead of the fixture, to the lower end of each pull-up rod in the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates in U-shape. According as the U-shape bending condition of the metal plate, the position of the adjust screw is caused to move and the rotary control force of the lower bar mold by the resilience of the push spring is adjusted by the change in the position of the adjust screw. Accordance as the bending condition of the metal plate, the metal plate is properly and neatly bent in U-shape. This is one of the features of the present invention.
Further, cushion material sheet, sliding surface or sintered carbide surface is formed on the metal contact surface/s, or either or both odd press parts of two (2) lower bar molds in the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates in U-shape. Thus, the formation of scratches, etc. is prevented on the lower surface of the metal plate. Thereby, this contributes to improvement in the metal plate as a product. This is one of the features of the present invention.
Furthermore, there is made as one unit the aforementioned apparatus of the present invention provided with rotary control function for bending metal plates in U-shape. A plurality of these units are caused to coexist lengthwise in one row. Thereby, the lengthy metal plate is bent in U-shape. This is one of the features of the present invention.